METHOD AND APPARATUS FOR SUPPRESSING FLOW-INDUCED JET PUMP VIBRATION IN A BOILING WATER REACTOR

摘要

Flow induced vibration (FIV) at the slip joint between a nuclear reactor jet pump mixer and diffuser is suppressed without installing additional parts or altering the jet pump construction. The disclosed method determines a relationship between reactor operating conditions that trigger FIV and the magnitude of a mixer/diffuser transverse contact load. A mathematical analysis on a representative jet pump configuration determines the quantitative relationship between mixer/diffuser cold positions and their positions when the reactor is operating. Thus, a prediction can be made as to whether an installed jet pump will experience FIV, and the mixer and diffuser can be positioned by a mixer adjustment tool when the reactor is cold to provide the necessary operational transverse contact load. Alternatively, a contact load measuring tool directly measures the magnitude and direction of the cold mixer/diffuser transverse contact load to determine if FIV will be suppressed when the reactor is operating.